using System;
using System.Net;
using System.IO;
using System.Text;
using System.Net.Sockets;

namespace FtpLib
{

   public class FTPFactory
   {

     private string remoteHost,remotePath,remoteUser,remotePass,mes;
     private int remotePort,bytes;
     private Socket clientSocket;

     private int retValue;
     private Boolean debug;
     private Boolean logined;
     private string reply;

     private static int BLOCK_SIZE = 512;

     Byte[] buffer = new Byte[BLOCK_SIZE];
     Encoding ASCII = Encoding.ASCII;

     public FTPFactory()
     {

       remoteHost  = "localhost";
       remotePath  = ".";
       remoteUser  = "anonymous";
       remotePass  = "jaimon@school2000.co.uk";
       remotePort  = 21;
       debug     = false;
       logined    = false;

     }

     ///
     /// Set the name of the FTP server to connect to.
     ///
     /// Server name
     public void setRemoteHost(string remoteHost)
     {
       this.remoteHost = remoteHost;
     }

     ///
     /// Return the name of the current FTP server.
     ///
     /// Server name
     public string getRemoteHost()
     {
       return remoteHost;
     }

     ///
     /// Set the port number to use for FTP.
     ///
     /// Port number
     public void setRemotePort(int remotePort)
     {
       this.remotePort = remotePort;
     }

     ///
     /// Return the current port number.
     ///
     /// Current port number
     public int getRemotePort()
     {
       return remotePort;
     }

     ///
     /// Set the remote directory path.
     ///
     /// The remote directory path
     public void setRemotePath(string remotePath)
     {
       this.remotePath = remotePath;
     }

     ///
     /// Return the current remote directory path.
     ///
     /// The current remote directory path.
     public string getRemotePath()
     {
       return remotePath;
     }

     ///
     /// Set the user name to use for logging into the remote server.
     ///
     /// Username
     public void setRemoteUser(string remoteUser)
     {
       this.remoteUser = remoteUser;
     }

     ///
     /// Set the password to user for logging into the remote server.
     ///
     /// Password
     public void setRemotePass(string remotePass)
     {
       this.remotePass = remotePass;
     }

     ///
     /// Return a string array containing the remote directory's file list.
     ///
     ///
     ///
     public string[] getFileList(string mask)
     {

       if(!logined)
       {
         login();
       }

       Socket cSocket = createDataSocket();

       sendCommand("NLST " + mask);

       if(!(retValue == 150 || retValue == 125))
       {
         throw new IOException(reply.Substring(4));
       }

       mes = "";

       while(true)
       {

         int bytes = cSocket.Receive(buffer, buffer.Length, 0);
         mes += ASCII.GetString(buffer, 0, bytes);

         if(bytes < buffer.Length)
         {
           break;
         }
       }

       char[] seperator = {'\n'};
       string[] mess = mes.Split(seperator);

       cSocket.Close();

       readReply();

       if(retValue != 226)
       {
         throw new IOException(reply.Substring(4));
       }
       return mess;

     }

     ///
     /// Return the size of a file.
     ///
     ///
     ///
     public long getFileSize(string fileName)
     {

       if(!logined)
       {
         login();
       }

       sendCommand("SIZE " + fileName);
       long size=0;

       if(retValue == 213)
       {
         size = Int64.Parse(reply.Substring(4));
       }
       else
       {
         throw new IOException(reply.Substring(4));
       }

       return size;

     }

     ///
     /// Login to the remote server.
     ///
     public void login()
     {

       clientSocket = new Socket(AddressFamily.InterNetwork,SocketType.Stream,ProtocolType.Tcp);
       IPEndPoint ep = new IPEndPoint(Dns.Resolve(remoteHost).AddressList[0], remotePort);

       try
       {
         clientSocket.Connect(ep);
       }
       catch(Exception)
       {
         throw new IOException("Couldn't connect to remote server");
       }

       readReply();
       if(retValue != 220)
       {
         close();
         throw new IOException(reply.Substring(4));
       }
       if(debug)
         Console.WriteLine("USER "+remoteUser);

       sendCommand("USER "+remoteUser);

       if( !(retValue == 331 || retValue == 230) )
       {
         cleanup();
         throw new IOException(reply.Substring(4));
       }

       if( retValue != 230 )
       {
         if(debug)
           Console.WriteLine("PASS xxx");

         sendCommand("PASS "+remotePass);
         if( !(retValue == 230 || retValue == 202) )
         {
           cleanup();
           throw new IOException(reply.Substring(4));
         }
       }

       logined = true;
       Console.WriteLine("Connected to "+remoteHost);

       chdir(remotePath);

     }

     ///
     /// If the value of mode is true, set binary mode for downloads.
     /// Else, set Ascii mode.
     ///
     ///
     public void setBinaryMode(Boolean mode)
     {

       if(mode)
       {
         sendCommand("TYPE I");
       }
       else
       {
         sendCommand("TYPE A");
       }
       if (retValue != 200)
       {
         throw new IOException(reply.Substring(4));
       }
     }

     ///
     /// Download a file to the Assembly's local directory,
     /// keeping the same file name.
     ///
     ///
     public void download(string remFileName)
     {
       download(remFileName,"",false);
     }

     ///
     /// Download a remote file to the Assembly's local directory,
     /// keeping the same file name, and set the resume flag.
     ///
     ///
     ///
     public void download(string remFileName,Boolean resume)
     {
       download(remFileName,"",resume);
     }

     ///
     /// Download a remote file to a local file name which can include
     /// a path. The local file name will be created or overwritten,
     /// but the path must exist.
     ///
     ///
     ///
     public void download(string remFileName,string locFileName)
     {
       download(remFileName,locFileName,false);
     }

     ///
     /// Download a remote file to a local file name which can include
     /// a path, and set the resume flag. The local file name will be
     /// created or overwritten, but the path must exist.
     ///
     ///
     ///
     ///
     public void download(string remFileName,string locFileName,Boolean resume)
     {
       if(!logined)
       {
         login();
       }

       setBinaryMode(true);

       Console.WriteLine("Downloading file "+remFileName+" from "+remoteHost + "/"+remotePath);

       if (locFileName.Equals(""))
       {
         locFileName = remFileName;
       }

       if(!File.Exists(locFileName))
       {
         Stream st = File.Create(locFileName);
         st.Close();
       }

       FileStream output = new FileStream(locFileName,FileMode.Open);

       Socket cSocket = createDataSocket();

       long offset = 0;

       if(resume)
       {

         offset = output.Length;

         if(offset > 0 )
         {
           sendCommand("REST "+offset);
           if(retValue != 350)
           {
             //throw new IOException(reply.Substring(4));
             //Some servers may not support resuming.
             offset = 0;
           }
         }

         if(offset > 0)
         {
           if(debug)
           {
             Console.WriteLine("seeking to " + offset);
           }
           long npos = output.Seek(offset,SeekOrigin.Begin);
           Console.WriteLine("new pos="+npos);
         }
       }

       sendCommand("RETR " + remFileName);

       if(!(retValue == 150 || retValue == 125))
       {
         throw new IOException(reply.Substring(4));
       }

       while(true)
       {

         bytes = cSocket.Receive(buffer, buffer.Length, 0);
         output.Write(buffer,0,bytes);

         if(bytes <= 0)
         {
           break;
         }
       }

       output.Close();
       if (cSocket.Connected)
       {
           cSocket.Close();
       }

       Console.WriteLine("");

       readReply();

       if( !(retValue == 226 || retValue == 250) )
       {
         throw new IOException(reply.Substring(4));
       }

     }

     ///
     /// Upload a file.
     ///
     ///
     public void upload(string fileName)
     {
       upload(fileName,false);
     }

     ///
     /// Upload a file and set the resume flag.
     ///
     ///
     ///
     public void upload(string fileName,Boolean resume)
     {

       if(!logined)
       {
         login();
       }

       Socket cSocket = createDataSocket();
       long offset=0;

       if(resume)
       {

         try
         {

           setBinaryMode(true);
           offset = getFileSize(fileName);

         }
         catch(Exception)
         {
           offset = 0;
         }
       }

       if(offset > 0 )
       {
         sendCommand("REST " + offset);
         if(retValue != 350)
         {
           //throw new IOException(reply.Substring(4));
           //Remote server may not support resuming.
           offset = 0;
         }
       }

       sendCommand("STOR "+Path.GetFileName(fileName));

       if( !(retValue == 125 || retValue == 150) )
       {
         throw new IOException(reply.Substring(4));
       }

       // open input stream to read source file
       FileStream input = new FileStream(fileName,FileMode.Open);

       if(offset != 0)
       {

         if(debug)
         {
           Console.WriteLine("seeking to " + offset);
         }
         input.Seek(offset,SeekOrigin.Begin);
       }

       Console.WriteLine("Uploading file "+fileName+" to "+remotePath);

       while ((bytes = input.Read(buffer,0,buffer.Length)) > 0)
       {

         cSocket.Send(buffer, bytes, 0);

       }
       input.Close();

       Console.WriteLine("");

       if (cSocket.Connected)
       {
           cSocket.Close();
       }

       readReply();
       if( !(retValue == 226 || retValue == 250) )
       {
         throw new IOException(reply.Substring(4));
       }
     }

     ///
     /// Delete a file from the remote FTP server.
     ///
     ///
     public void deleteRemoteFile(string fileName)
     {

       if(!logined)
       {
         login();
       }

       sendCommand("DELE "+fileName);

       if(retValue != 250)
       {
         throw new IOException(reply.Substring(4));
       }

     }

     ///
     /// Rename a file on the remote FTP server.
     ///
     ///
     ///
     public void renameRemoteFile(string oldFileName,string 
newFileName)
     {

       if(!logined)
       {
         login();
       }

       sendCommand("RNFR "+oldFileName);

       if(retValue != 350)
       {
         throw new IOException(reply.Substring(4));
       }

       //  known problem
       //  rnto will not take care of existing file.
       //  i.e. It will overwrite if newFileName exist
       sendCommand("RNTO "+newFileName);
       if(retValue != 250)
       {
         throw new IOException(reply.Substring(4));
       }

     }

     ///
     /// Create a directory on the remote FTP server.
     ///
     ///
     public void mkdir(string dirName)
     {

       if(!logined)
       {
         login();
       }

       sendCommand("MKD "+dirName);

       if(retValue != 250)
       {
         throw new IOException(reply.Substring(4));
       }

     }

     ///
     /// Delete a directory on the remote FTP server.
     ///
     ///
     public void rmdir(string dirName)
     {

       if(!logined)
       {
         login();
       }

       sendCommand("RMD "+dirName);

       if(retValue != 250)
       {
         throw new IOException(reply.Substring(4));
       }

     }

     ///
     /// Change the current working directory on the remote FTP server.
     ///
     ///
     public void chdir(string dirName)
     {

       if(dirName.Equals("."))
       {
         return;
       }

       if(!logined)
       {
         login();
       }

       sendCommand("CWD "+dirName);

       if(retValue != 250)
       {
         throw new IOException(reply.Substring(4));
       }

       this.remotePath = dirName;

       Console.WriteLine("Current directory is "+remotePath);

     }

     ///
     /// Close the FTP connection.
     ///
     public void close()
     {

       if( clientSocket != null )
       {
         sendCommand("QUIT");
       }

       cleanup();
       Console.WriteLine("Closing...");
     }

     ///
     /// Set debug mode.
     ///
     ///
     public void setDebug(Boolean debug)
     {
       this.debug = debug;
     }

     private void readReply()
     {
       mes = "";
       reply = readLine();
       retValue = Int32.Parse(reply.Substring(0,3));
     }

     private void cleanup()
     {
       if(clientSocket!=null)
       {
         clientSocket.Close();
         clientSocket = null;
       }
       logined = false;
     }

     private string readLine()
     {

       while(true)
       {
         bytes = clientSocket.Receive(buffer, buffer.Length, 0);
         mes += ASCII.GetString(buffer, 0, bytes);
         if(bytes < buffer.Length)
         {
           break;
         }
       }

       char[] seperator = {'\n'};
       string[] mess = mes.Split(seperator);

       if(mes.Length > 2)
       {
         mes = mess[mess.Length-2];
       }
       else
       {
         mes = mess[0];
       }

       if(!mes.Substring(3,1).Equals(" "))
       {
         return readLine();
       }

       if(debug)
       {
         for(int k=0;k < mess.Length-1;k++)
         {
           Console.WriteLine(mess[k]);
         }
       }
       return mes;
     }

     private void sendCommand(String command)
     {

       Byte[] cmdBytes = Encoding.ASCII.GetBytes((command+"\r\n").ToCharArray());
       clientSocket.Send(cmdBytes, cmdBytes.Length, 0);
       readReply();
     }

     private Socket createDataSocket()
     {

       sendCommand("PASV");

       if(retValue != 227)
       {
         throw new IOException(reply.Substring(4));
       }

       int index1 = reply.IndexOf('(');
       int index2 = reply.IndexOf(')');
       string ipData = reply.Substring(index1+1,index2-index1-1);
       int[] parts = new int[6];

       int len = ipData.Length;
       int partCount = 0;
       string buf="";

       for (int i = 0; i < len && partCount <= 6; i++)
       {

         char ch = Char.Parse(ipData.Substring(i,1));
         if (Char.IsDigit(ch))
           buf+=ch;
         else if (ch != ',')
         {
           throw new IOException("Malformed PASV reply: " + reply);
         }

         if (ch == ',' || i+1 == len)
         {

           try
           {
             parts[partCount++] = Int32.Parse(buf);
             buf="";
           }
           catch (Exception)
           {
             throw new IOException("Malformed PASV reply: " +  reply);
           }
         }
       }

       string ipAddress = parts[0] + "."+ parts[1]+ "." + parts[2] + "." + parts[3];
       int port = (parts[4] << 8) + parts[5];

       Socket s = new Socket(AddressFamily.InterNetwork,SocketType.Stream,ProtocolType.Tcp);
       IPEndPoint ep = new IPEndPoint(Dns.Resolve(ipAddress).AddressList[0], port);

       try
       {
         s.Connect(ep);
       }
       catch(Exception)
       {
         throw new IOException("Can't connect to remote server");
       }
       return s;
     }

   }
}



//public class Test {

//   public static void Main() {

//     try {

//       Console.WriteLine("Starting...");

//       FTPFactory ff = new FTPFactory();
//       ff.setDebug(true);
//       ff.setRemoteHost("192.168.0.30");
//       ff.setRemoteUser("jaimon");
//       ff.setRemotePass("mathew");
//       ff.login();
//       ff.chdir("incoming");

//       string[] fileNames = ff.getFileList("*.*");
//       for(int i=0;i < fileNames.Length;i++) {
//         Console.WriteLine(fileNames[i]);
//       }

//       ff.setBinaryMode(true);
//       ff.upload("c:\jaimon\tmp\Webdunia.ttf");
//       ff.close();

//     }catch(Exception e) {
//       Console.WriteLine("Caught Error :"+e.Message);
//     }
//   }
//}

